Hollow sole for footwear and manufacturing method therefor

ABSTRACT

Footwear sole comprising a top half with hollow vertical configurations and a bottom half, wherein said configurations are filled to at least half of their volume with a shock-absorbing plastic material to absorb as great a range of possible loads with a simple and easily adjustable configuration.

TECHNICAL FIELD OF THE INVENTION

The present invention lies in the field of hollow soles for footwear.

This invention is a hollow sole for footwear that combines several cushioning methods meant to absorb the greatest range of possible loads with a simple and easily adjustable configuration.

BACKGROUND OF THE INVENTION

Hollow soles for footwear are known formed by two parts joined to each other to configure a hollow part between them that is filled with air, as shown by the same applicant in Spanish Utility Model with application number 201030592.

This type of sole is convenient for different uses due to its shock-absorbing qualities, which are inherent to the configuration of the sole, which results in a specific mechanical behaviour. For this reason, modifications in the shock-absorbing properties are meant to modify the configurations that are compressed, normally truncated pyramids or prisms, as well as modifying the type of material used to manufacture the sole, which will provide the restoration from the compression.

Other known types of sole use solid configurations of different plastic components, combining different hardness and elastic properties. In this case, however, the soles tend to have poor lateral support, as it is the structure of the plastic material that must withstand the lateral load, so that it is not uncommon to see feet with excessive pronation or supination.

In both hollow and solid soles, once a problem is known and the corresponding adjustment is decided, it is complicated and expensive to carry it out, as it involves acting on a single factor, either the configuration or the material, which has a working range that may be inadequate for solving the problem.

Thus, configurations made of rubber in hollow soles of geometric type, such as truncated cones and others, are suitable for absorbing high impact forces, such as the first contact of the heel with the ground. However, plastic foams in solid soles are suitable for medium and small impacts, such as during foot roll and toe lift.

For this reason, no soles are known that combine in an optimum manner several cushioning methods to cover a wide range of loads and that are easily adjustable while designing the sole. That is, on one hand a structure made of a strong material, normally rubber, that supports greater loads and provides the support pillars for said structure, and on the other components that support smaller loads and that generally provide a sensation of comfort to the user.

The present invention discloses a sole that combines several cushioning methods meant to solve the drawbacks of the state of the art and absorb the greatest range of possible loads with a simple and easily adjustable configuration.

DESCRIPTION OF THE INVENTION

The present invention is established and characterised in the independent claims, while the dependent claims describe additional characteristics thereof.

In view of the foregoing, the present invention relates to a hollow sole for footwear that comprises a bottom half and a top half, the top half in turn comprising a sheet and hollow vertical configurations that define internal pockets, with the hollow base integrated in said sheet, and said hollow vertical configurations being oriented towards the inside of the sole, the bottom half being disposed such that it contacts the surfaces of the hollow vertical configurations that face the inside of the sole, wherein the internal pockets of the hollow vertical configurations of the top half are at least half-filled by a shock-absorbing plastic material.

BRIEF DESCRIPTION OF THE DRAWINGS

This specification is supplemented with a set of drawings illustrating the preferred embodiment, which are never intended to limit the invention.

FIG. 1 represents a cross section of an embodiment in which the shock-absorbing material reaches beyond the top part of the top half.

FIG. 2 represents a cross section of the same embodiment in which the shock-absorbing material does not reach beyond the top part of the top half.

FIG. 3 represents a cross section of another embodiment in which the shock-absorbing material reaches beyond the top part of the top half.

FIG. 4 represents a cross section of the same embodiment in which the shock-absorbing material does not reach beyond the top part of the top half.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

An embodiment of the invention is described in what follows wherein the sole comprises a bottom half (1) and a top half (2), in the form of two shells or one shell and a lid, such that air is trapped inside it, between the two halves (1,2), which air can be at atmospheric pressure or at a greater pressure in order to cushion shocks when striking the ground. To ensure that the pressure is maintained, in the top half (2) normally an orifice is made (not shown) that is either sealed or is provided with a flow-control valve, of those known, to the internal pocket defined between the two halves (1,2).

The top half (2) in turn comprises a sheet (2.1) and hollow vertical configurations (2.2) that form internal pockets (2.3), with the base being integrated in said sheet (2.1), said hollow vertical configurations (2.2) being oriented towards the inside of the sole. This is, the hollow configurations (2.2) are integrated in the sheet (2.1) to form a single continuous surface.

In one embodiment, the other half (1) is disposed such that it contacts the surface of the hollow vertical configurations (2.2) that is facing the inside of the sole. In this way, the bottom half (1) acts as a cover and as the part of the sole that contacts the ground.

The above configuration provides cushioning due to the elasticity of the sole material, normally rubber, together with the mechanical characteristics of the hollow vertical configurations (2.2), which are normally truncated cones, cylinders or prisms. There is a second cushioning provided by the compression of air caused by each step, whether or not the air is at a pressure above atmospheric pressure, as in the step the internal volume of the sole is always reduced by the compression of the material that allows the hollow vertical configurations (2.2) to compress and later recover their original shape.

These two cushioning forms are those known in hollow soles; in this embodiment, a third form is added by filling the internal pockets (2.3) of the hollow configurations of the top half to at least half of their volume, or even completely, with a shock-absorbing plastic material (3). In this way, in the step the elastic characteristics of the footwear sole material are combined with hollow vertical configurations (2.2) filled with a specific material appropriate for the mechanical loads of the step, so that the impact is absorbed better and the recovery is optimised, as well as providing a feeling of comfort and safety to the user.

In a variant of the above-described embodiment the two halves (1,2) are similar, that is, the bottom half (1) comprises a sheet (1.1) and hollow vertical configurations (1.2), which form internal pockets (1.3), the base being integrated in said sheet (1.1) so that said hollow vertical configurations (1.2) are facing the inside of the sole, such that they contact the surfaces of the hollow configurations (1.2,2.2) facing the inside of the sole in each of the halves (1,2).

In this case it may be convenient to add an additional sheet (5) acting as a sole in contact with the ground.

In this variant, the hollow vertical configurations (1.2, 2.2) are duplicated and act jointly, with the two halves (1,2) opposite each other, resulting in a greater cushioning, in other words, adjusting to a different cushioning scale, as the fine adjustment of the cushioning in any of the embodiments shown is performed by combining all the variables involved: material of the halves, air compression between the halves, geometry of the hollow vertical configurations (1.2, 2.2) and filler material (3) therefor.

As stated above, the hollow vertical configurations (1.2,2.2) are preferably truncated pyramids, truncated cones, cylinders or prisms.

An advantageous manner of filling the hollow vertical configurations (2.2) of the top half (2) is filling them to the top surface of the latter. In this way, the shoe cut closes directly on the top half (2) of the sole.

Another advantageous manner of filling the hollow configurations (2.2) of the top half (2) is until passing the upper surface of the top half (2), so that a sheet (3.1) is created above the top half made of the shock-absorbing plastic material (3). The shoe cut will then be placed on top of this sheet (3.1).

Both advantageous variants can include through orifices (2.4, 3.2) that place the hollow inside of the sole with the cut, and thus with the user's foot, directly in contact with the air chamber between the two halves (1,2). In this way the foot will be cooled better in warm weather. It is clear that as the air chamber is communicated with the outside, the air in it can never be at a pressure greater than atmospheric pressure.

Specifically, in the embodiment with the sheet (3.1) above the top half (2) of the shock-absorbing plastic material (3), this half (2) has through orifices (2.4) that coincide with the through orifices (3.2) of the sheet (3.1) of the top half (2).

In addition to the three aforementioned cushioning methods, a fourth one can be added that consists in using the gas generated when setting the materials so that in the hollow configurations of the (2.2) of the top half, a gas chamber (4) is defined between the front of the shock-absorbing material (3) and the free surface (2.2.1), by which is meant the surface that is not the base integrated in the sheet (2.1) that is facing the inside of the sole, of the hollow configurations (2.2).

Preferably, the shock-absorbing plastic material (3) used is polyurethane.

The manufacturing method for a footwear sole as described above always includes the following stages:

-   -   moulding the top half (2),     -   moulding the bottom half (1),     -   joining the two halves (1,2),     -   introducing the shock-absorbing material (3) to the top half (2)         by injection or casting.

When the sole is of the type in which the shock-absorbing material (3) does not extend beyond the top surface of the top half (2), before introducing the shock-absorbing material (3) in the top half (2) the shoe cut is placed flush against the top half (2), so that this cut acts as a countermould.

Instead, when the shoe cut is not placed because the shock-absorbing material (3) extends beyond the top surface of the top half (2), before introducing the shock-absorbing material (3) in the top half (2) it will be necessary to place a countermould in order to leave a space between the top half (2) and said countermould, so that the shock-absorbing material (3) approximately forms a sheet (3.1) above the top half (2) of the sole. 

1. Hollow sole for footwear that comprises a bottom half (1) and a top half (2), the top half (2) in turn comprising a sheet (2.1) and hollow vertical configurations (2.2) that define internal pockets (2.3), the hollow base being integrated in said sheet (2.1), said hollow vertical configurations (2.2)being oriented towards the inside of the sole, the bottom half (1) being disposed such that it contacts the surfaces of the hollow vertical configurations (2.2) that face the inside of the sole, characterised in that the internal pockets (2.3) of the hollow vertical configurations (2.2) of the top half (2) are half-filled by a shock-absorbing plastic material (3).
 2. Hollow sole for footwear according to claim 1, characterised in that the bottom half (1) comprises a sheet (1.1) and hollow vertical configurations (1.2), which form internal pockets (1.3), the base being integrated in said sheet (1.1) so that said hollow vertical configurations (1.2) face the inside of the sole such that they contact the surfaces of the hollow configurations (1.2,2.2) facing the inside of the sole in each of the halves (1,2).
 3. Hollow sole for footwear according to claim 1 or 2, characterised in that the hollow vertical configurations (1.2,2.2) are truncated pyramids, truncated cones, cylinders or prisms.
 4. Hollow sole for footwear according to claim 1 or 2, characterised in that the hollow vertical configurations (2.2) of the top half (2) are filled up to the top surface of the top half (2).
 5. Hollow sole for footwear according to claim 1 or 2, characterised in that the hollow vertical configurations (2.2) of the top half (2) are filled beyond the upper surface of the top half (2), so that a sheet (3.1) is created above the top half (2) made of the shock-absorbing plastic material (3).
 6. Hollow sole for footwear according to claim 1 or 2, characterised in that the hollow vertical configurations (2.2) of the top half (2) are filled such that a gas chamber (4) is left between the front of the shock-absorbing material (3) and the free surface (2.2.1) of the hollow vertical configurations (2.2).
 7. Hollow sole for footwear according to the above claims, characterised in that the shock-absorbing plastic material (3) is polyurethane.
 8. Hollow sole for footwear according to claim 1 or 2, characterised in that the sheet (2.1) of the top half (2) includes through orifices (2.4).
 9. Hollow sole for footwear according to claim 8, characterised in that the sheet (3.1) above the top half (2) of the shock-absorbing plastic material (3), this half (2) has through orifices (3.2) that coincide with the through orifices (2.4) of the sheet (2.1) of the top half (2).
 10. Manufacturing method for a footwear sole according to the above claims, characterised in that it comprises the following stages: moulding the top half (2), moulding the bottom half (1), joining the two halves (1,2), introducing the shock-absorbing material (3) to the top half (2) by injection or casting.
 11. Manufacturing method for a footwear sole according to claim 10, characterised in that before introducing the shock-absorbing material (3) in the top half (2) the shoe cut is placed flush on the top half (2).
 12. Manufacturing method for a footwear sole according to claim 10, characterised in that before introducing the shock-absorbing material (3) in the top half (2), a countermould is placed to leave a space between the top half (2) and said countermould so that the shock-absorbing material (3) forms approximately a sheet (3.1) on the top half (2) of the sole.
 13. Manufacturing method for a footwear sole according to claim 10, characterised in that the shock-absorbing plastic material (3) is polyurethane. 